A technology for circulating a cooling water in order to cool and/or warm an engine is known heretofore. For example, a Patent Literature 1 discloses a technology for increasing a ratio of a driving power outputted by the engine by an amount which depends on a difference between a temperature of the cooling water which is required for a desired heating and a current temperature of the cooling water (namely, changing an operation of the engine such that an amount of a heat generation of the engine increases). As a result, the technology which is disclosed in the Patent Literature 1 allows the temperature of the cooling water to promptly reach a target value (namely, the temperature of the cooling water which is required for the desired heating).
In addition, a Patent Literature 2 is listed as a background art which is related to the present invention. The Patent Literature 2 discloses a technology for limiting an output of the engine and a motor when a temperature of the engine and the motor reaches an upper limit value at which an output limitation is required.